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Meanwhile, the Nobel prize for medicine went to two stem cell researchers from Japan and the UK.

John Gurdon of the Gurdon Institute in Cambridge and Shinya Yamanaka of Kyoto University, discovered ways to create tissue that would act like embryonic cells, without the need to collect the cells from embryos.

The Nobel committee said their work had revolutionised science.

Stem cells have shown huge potential for the development of treatments for a range of conditions, including Parkinson's Disease, heart disease, strokes and spinal cord damage.

In 1962, Prof Gurdon became the first scientist to clone an animal, making a healthy tadpole from the egg of a frog with DNA from another tadpole's intestinal cell.

That showed that developed cells carry the information to make every cell in the body - decades before other scientists made world headlines by cloning the first mammal from adult DNA, Dolly the sheep.

More than 40 years later, Prof Yamanaka produced mouse stem cells from adult mouse skin cells by inserting a small number of genes.

His breakthrough effectively showed that the development that takes place in adult tissue could be reversed, turning adult tissue back into cells that behave like embryos.

Stem cells created from adult tissue are known as "induced pluripotency stem cells", or iPS cells.

Because patients may one day be treated with stem cells from their own tissue, their bodies might be less likely to reject them.